Human population on Earth is affecting both the atmosphere and the ecosystems. A. The survival of organisms on Earth is directly related to the amount of fossil fuels that are consumed. B. Atmospheric carbon dioxide concentrations are rising quickly. C. Scientists are working on ways to make precise forecasts of how the increase of greenhouse gases will affect Earth. D. Scientists predict that temperature changes would be greater at the poles than at the equator. E. Global circulation models can be used to measure the concentrations of chlorofluorocarbons in the atmosphere. F. The ability to make accurate predictions about global climate presents several difficulties.